The Bowen Basin spans roughly 200,000 km2 of eastern Australia, covering a large area of eastern Queensland and part of northern NSW (Cadman et al., 1998). In the Maranoa-Balonne-Condamine subregion, the Surat Basin, which is part of the GAB, overlies the southern Bowen Basin, and also extends beyond the margins of these older stratigraphic sequences (Figure 17). However, the main depositional centres of both the Bowen and Surat basins are co-located (the Taroom Trough and Mimosa Syncline, respectively), meaning that the thickest stratigraphic sequences in both basins occur in roughly similar locations.

The Surat Basin covers approximately 300,000 km2, and like the Bowen Basin occurs in Queensland and NSW (Exon, 1976). The Clarence-Moreton Basin, the north-western part of which is part of the GAB, is small in comparison, about 38,000 km2 and is adjacent to the Surat Basin (note that the size of the Clarence-Moreton Basin is inaccurate in some older publications). It also occurs in southern Queensland and northern NSW.

The Bowen, Surat and Clarence-Moreton basins are intracratonic sedimentary basins that have been variably affected by tectonic deformation. These processes have widely caused faulting, folding, volcanic activity and subsidence throughout the basins (Cadman et al., 1998).

There are currently no formally recognised sub-basins for either the Bowen or Surat basins. However, the Bowen and Surat basins are divided into distinct regions based on the structural features that control both the location and thickness of the sedimentary sequences. The main structural features of the Maranoa-Balonne-Condamine subregion are displayed in Figure 18.

The Clarence-Moreton Basin is composed of three sub-basins: the Cecil Plains Sub-basin, the Laidley Sub-basin and the Logan Sub-basin (Martin and Saxby, 1982). The latter two are outside the Maranoa-Balonne-Condamine subregion and only a portion of the Cecil Plains Sub-basin falls within the subregion. Some authors suggest that due to the continuation of sedimentation and other geological similarities between the Surat Basin and the Cecil Plains Sub-basin, the Cecil Plains Sub-basin should form part of the Surat Basin and not the Clarence-Moreton Basin (Jell et al., 2013).

The Bowen Basin is bounded to the east by north-striking faults, including a Triassic thrust system that extends south of the Auburn Arch (Cadman et al., 1998). The Taroom Trough is the major sediment depositional centre in the basin and extends throughout the Maranoa-Balonne-Condamine subregion (Cadman et al., 1998; Draper, 2013). It formed during crustal extension in the Late Carboniferous to Early Permian (McKellar, 1998; Fielding et al., 1993). In the south-west of the Bowen Basin, sedimentary sequences pinch-out and thin over the Nebine Ridge and Saint George-Bollon Slope (Figure 18) (Cadman et al., 1998; Draper, 2013). Half-grabens in the Denison and Taroom troughs are evidence of Late Carboniferous and Early Permian tectonic extension (Cadman et al., 1998; Elliott, 1989). To the west, in the central Bowen Basin, the Springsure Shelf is a half-graben that marks the western boundary of the basin (Draper, 2013). Faulting in the southern Bowen Basin is dominantly north-south oriented. Most faults have normal displacement, although many recent faults are reverse faults (Draper, 2013).

The Clarence-Moreton Basin is bounded by older granitic and metamorphic basement blocks. Major post-Triassic uplift created the synclinal depression of the Cecil Plains, forming the Cecil Plains Sub-basin, one of the main structural features in the north-western Clarence-Moreton Basin (Jell et al., 2013). The Cecil Plains Sub-basin sits on top of the Horrane Trough, a half-graben feature thought to have formed during strike-slip faulting (Jell et al., 2013). Other significant structural features within the basin are the Helidon Ridge, Gatton Arch, and a small portion of the Richmond Horst is in the subregion (Cadman et al., 1998; Johnstone et al., 1985). The Gatton Arch is outside of the Maranoa-Balonne-Condamine subregion, but forms the main separation zone of the two northern sub-basins.